Terminal apparatus, base station apparatus, communication system, communication method, and integrated circuit

ABSTRACT

A serving cell in a dormant state transmits discovery signals to let mobile station devices be aware of its presence. The mobile station devices are configured with a series of discovery signal candidates, which they monitor in the discovery signal burst subframes. A mobile station device detecting a particular discovery signal candidate can make some assumptions relative to the dormant cell.

TECHNICAL FIELD

The present document describes methods and processes applicable towireless communication systems, with a focus on a discovery signal usedby some dormant cells in LTE to make mobile station devices aware oftheir existence.

BACKGROUND ART

The Third Generation Partnership Project (3GPP) is constantly studyingthe evolution of the radio access schemes and radio networks forcellular mobile communications (hereinafter referred to as “Long TermEvolution (LTE)” or “Evolved Universal Terrestrial Radio Access(EUTRA)”. In LTE, the Orthogonal Frequency Division Multiplexing (OFDM)scheme, which is a multi-carrier transmission scheme, is used as acommunication scheme for wireless communication from a base stationdevice (hereinafter also referred to as “base station apparatus”, “basestation”, “eNB”, “access point”) to a mobile station device (hereinafter also referred to as “mobile station”, “terminal station”,“terminal station apparatus”, “user equipment”, “UE”, “user”). The basestation device has one or more serving cells configured (hereinafteralso referred to as “cell”), and the communication with the mobilestation device is performed through them. Also, the Single-CarrierFrequency Division Multiple Access (SC-FDMA) scheme, which is asingle-carrier transmission scheme, is used as a communications schemefor wireless communication from a mobile station device to a basestation device (uplink)

In 3GPP, studies are being performed to allow radio access schemes andradio networks which realize higher-speed data communication using abroader frequency band than that of LTE (hereinafter referred to as“Long Term Evolution-Advanced (LTE-A)” or “Advanced Evolved UniversalTerrestrial Radio Access (A-EUTRA)”) to have backward compatibility withLTE. That is, a base station device of LTE-A is capable ofsimultaneously performing wireless communication with mobile stationdevices of both LTE-A and LTE, and a mobile station device of LTE-A iscapable of performing wireless communication with base station devicesof both LTE-A and LTE. The channel structure of LTE-A is the same asthat of LTE, and it is described in Non Patent Literature (NPL) 1 and 2.

In LTE, the base station device transmits the control informationthrough the Physical Downlink Control Channel (PDCCH) or the enhancedPDCCH (ePDCCH or EPDCCH). The mobile stations monitor the PDCCH regionlooking for messages directed to them, more specifically a subspace ofthat region called “search space”. The search space to monitor formessages specifically addressed to the individual mobile station devicesis called User Search Space (USS). The search space to monitor to lookfor messages addressed to a particular mobile station device or a groupthereof is called Common Search Space (CSS). In the ePDCCH case, themobile station devices monitor a subspace of the ePDCCH region lookingfor messages specifically addressed to the individual mobile stationdevices (ePDCCH USS). The base station device can configure the mobilestation devices through the use of Radio Resource Control (RRC)messages, as described in NPL 3.

LTE allows two or more serving cells to be aggregated to increase thepeak data rate a mobile station device is capable of achieving.Typically a mobile station device sends its uplink control informationthrough the PUSCH (Physical Uplink Control Channel) of only one cell,which is known as the primary cell, although LTE is investigating waysto allow mobile station device to transmit this information to secondarycells as well.

In some cases some cells can be deactivated, entering into a dormantstate, under certain load conditions of the network. These cells can bereactivated to supplement the capacity when needed. Dormant cellsperiodically broadcast a discovery signal to allow mobile stationdevices to detect their presence.

CITATION LIST Non Patent Literature

NPL 1: 3rd Generation Partnership Project; Technical Specification GroupRadio Access Network; Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation (Release 11), 3GPP TS36. 211v11. 5. 0.(2013-12)<URL:http://www.3gpp.org/ftp/Specs/html-info/36211.htm>

NPL 2: 3rd Generation Partnership Project; Technical Specification GroupRadio Access Network; Evolved Universal Terrestrial Radio Access(E-UTRA); Physical layer procedures (Release 11), 3GPP TS36. 213 v11. 5.0. (2013-12)<URL:http://www.3gpp.org/ftp/Specs/html-info/36213.htm>

NPL 3: 3rd Generation Partnership Project; Technical Specification GroupRadio Access Network; Evolved Universal Terrestrial Radio Access(E-UTRA); Radio Resource Control (RRC); Protocol specification (Release11), 3GPP TS36. 331 v11. 6. 0.(2013-12)<URL:http://www.3gpp.org/ftp/Specs/html-info/36331.htm>

SUMMARY OF INVENTION Technical Problem

In the related art a serving cell is capable of entering a low energyconsumption mode (off state, or dormancy). A cell in the dormant statedoes not transmit normal signals, achieving energy saving and avoidinginterfering neighboring cells. However, it is unclear how the mobilestation devices can detect the presence of a dormant cell in theirsurroundings and decide if they want to report the cell to anotheractive cell (triggering the decision of whether to wake the dormant cellup or not) or if they wait for the dormant cell to wake up if the cellis already in the process of doing that.

The present invention has been made in view of the above-describedpoints, and an object thereof is to provide a mobile station device, abase station device, a wireless communication system, a wirelesscommunication method, and an integrated circuit enabling a scenario inwhich the mobile station device can detect a dormant cell and roughlydiscern between different states the dormant cell may be in.

Solution to Problem

(1) The present invention has been made to solve the above-describedproblem, and according to one embodiment of the present invention, thereis provided a mobile station device comprising a first circuitconfigured with a plurality of discovery signal candidates; and a secondcircuit adapted to perform monitoring for the discovery signalcandidates; and a third circuit adapted to identify a detected discoverysignal with one of the discovery signal candidates.

(2) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the discovery signal candidates differ between them in the combinationof reference signals they are configured with, a first discovery signalcandidate being based on a combination of reference signals; and asecond discovery signal candidate being based on a different combinationof reference signals; and subsequently configured discovery signalcandidates being based on a combination of reference signals that isdifferent from the combination of reference signals of the previouslyconfigured discovery signal candidates.

(3) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the discovery signal candidates differ between them in the subset ofsubframes within the discovery signal burst they are transmitted on, afirst discovery signal candidate being transmitted on a subset ofsubframes; and a second discovery signal candidate being transmitted ona different subset of subframes; and subsequently configured discoverysignal candidates being transmitted on a subset of subframes that isdifferent from the subset of subframes of the previously configureddiscovery signal candidates.

(4) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the discovery signal candidates differ between them in the subset ofresource elements within the physical resource block they aretransmitted on, a first discovery signal candidate being transmitted ona subset of resource elements; and a second discovery signal candidatebeing transmitted on a different subset of resource elements; andsubsequently configured discovery signal candidates being transmitted ona subset of resource elements that is different from the subset ofresource elements of the previously configured discovery signalcandidates.

(5) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the discovery signal candidates differ between them in the transmissionpower used for their transmission, a first discovery signal candidatebeing transmitted with a given transmission power; and a seconddiscovery signal candidate being transmitted with a differenttransmission power; and subsequently configured discovery signalcandidates being transmitted with a transmission power that is differentfrom the transmission power of the previously configured discoverysignal candidates.

(6) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the discovery signal candidates differ between them in the period theyare transmitted with, the period being a multiple of the period of thediscovery signal burst, a first discovery signal candidate beingtransmitted with a given period; and a second discovery signal candidatebeing transmitted with a different period; and subsequently configureddiscovery signal candidates being transmitted with a period that isdifferent from the period of the previously configured discovery signalcandidates.

(7) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the mobile station device assumes a state or set of parameters of theserving cell transmitting a detected discovery signal based on thediscovery signal candidate the detected discovery signal matches with.

(8) A mobile station device according to another aspect of the presentinvention is constituted such that the mobile station device abovefurther comprises a circuit to compare the RRM measurement of thedetected discovery signals' cells; and another circuit to report to theprimary serving cell the identities of the cells with the largest RRMmeasured values.

(9) A mobile station device according to another aspect of the presentinvention is constituted such that the mobile station device abovefurther comprises a circuit to compare the RRM measurement of thedetected discovery signals' cells; and another circuit to monitor thePDCCH/EPDCCH of a cell whose detected discovery signal's RRM measurementis over a configured threshold and matches one of the configureddiscovery signal candidates.

(10) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the RRM measurements is performed with an offset whose value depends onthe configured discovery signal candidate the discovery signal matcheswith before performing RRM measurement comparisons.

(11) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,the mobile station device starts a procedure for cell detection in acell whose discovery signal matches one of the configured discoverysignal candidates.

(12) A mobile station device according to another aspect of the presentinvention is constituted such that the mobile station device abovefurther comprises a circuit to prepare a first RRM report format for RRMmeasurements of discovery signals matching a first subset of discoverysignal candidates; and another circuit to prepare a second RRM reportformat for RRM measurements of discovery signals matching the discoverysignal candidates that are not part of the first subset.

(13) A mobile station device according to another aspect of the presentinvention is constituted such that the mobile station device abovefurther comprises a circuit to compare the RRM measurement values of thedetected discovery signals, wherein the mobile station device preparesonly the first or the second RRM report format based on the discoverysignal candidate the detected discovery signal with the largest RRMmeasurement value matches with.

(14) A mobile station device according to another aspect of the presentinvention is constituted such that, in the mobile station device above,a non-transitory computer-readable medium comprises computer-executableinstructions for causing one or more processors and/or memory to performthe communication method described above.

(15) According to one embodiment of the present invention, there isprovided a base station device comprising a first circuit configuredwith a plurality of discovery signal candidates; and a second circuitadapted to select a discovery signal candidate according to a set ofconfigured conditions; and a third circuit adapted to prepare andtransmit the selected discovery signal candidate.

(16) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above,the discovery signal candidates differ between them in the combinationof reference signals they are configured with, a first discovery signalcandidate being based on a combination of reference signals; and asecond discovery signal candidate being based on a different combinationof reference signals; and subsequently configured discovery signalcandidates being based on a combination of reference signals that isdifferent from the combination of reference signals of the previouslyconfigured discovery signal candidates.

(17) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above,the discovery signal candidates differ between them in the subset ofsubframes within the discovery signal burst they are transmitted on, afirst discovery signal candidate being transmitted on a subset ofsubframes; and a second discovery signal candidate being transmitted ona different subset of subframes; and subsequently configured discoverysignal candidates being transmitted on a subset of subframes that isdifferent from the subset of subframes of the previously configureddiscovery signal candidates.

(18) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above,the discovery signal candidates differ between them in the subset ofresource elements within the physical resource block they aretransmitted on, a first discovery signal candidate being transmitted ona subset of resource elements; and a second discovery signal candidatebeing transmitted on a different subset of resource elements; andsubsequently configured discovery signal candidates being transmitted ona subset of resource elements that is different from the subset ofresource elements of the previously configured discovery signalcandidates.

(19) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above,the discovery signal candidates differ between them in the transmissionpower used for their transmission, a first discovery signal candidatebeing transmitted with a given transmission power; and a seconddiscovery signal candidate being transmitted with a differenttransmission power; and subsequently configured discovery signalcandidates being transmitted with a transmission power that is differentfrom the transmission power of the previously configured discoverysignal candidates.

(20) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above,the discovery signal candidates differ between them in the period theyare transmitted with, the period being a multiple of the period of thediscovery signal burst, a first discovery signal candidate beingtransmitted with a given period; and a second discovery signal candidatebeing transmitted with a different period; and subsequently configureddiscovery signal candidates being transmitted with a period that isdifferent from the period of the previously configured discovery signalcandidates.

(21) A base station device according to another aspect of the presentinvention is constituted such that, in the base station device above, anon-transitory computer-readable medium comprises computer-executableinstructions for causing one or more processors and/or memory to performthe communication method described above.

Advantageous Effects of Invention

According to the present invention, a mobile station device is capableof detecting the presence of a dormant cell and roughly discern betweendifferent states the dormant cell may be in.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of a wireless communication systemaccording to the first embodiment.

FIG. 2 is a diagram illustrating an example of a downlink OFDM structureconstruction according to the present invention.

FIG. 3 is a diagram illustrating an example of a legacy physicalresource block with some of its defined reference signals according tothe present invention.

FIG. 4 is a diagram illustrating an example of a legacy physicalresource block with positioning reference signals (PRS) according to thepresent invention.

FIG. 5 is a diagram illustrating an example of a downlink OFDM structureconstruction with primary and synchronization signals according to thepresent invention.

FIG. 6 is a diagram illustrating an example of an uplink OFDM structureconstruction according to the present invention.

FIG. 7 is a diagram illustrating the allocation of physical uplinkresources to PUCCH and PUSCH according to the present invention.

FIG. 8 is a diagram illustrating an example of the configuration ofradio frames in a TDD wireless communication system according to thepresent invention.

FIG. 9 is a table illustrating the uplink-downlink configurations thatare possible in a TDD wireless communication system according to thepresent invention.

FIG. 10 is a diagram illustrating an example of mobile station devicecomposition according to the present invention.

FIG. 11 is a diagram illustrating an example of base station devicecomposition according to the present invention.

FIG. 12 is a table illustrating an example of UE-specific and commonsearch space configuration for PDCCH in a wireless communication systemaccording to the present invention.

FIG. 13 is a diagram illustrating an example of mapping of a physicalEPDCCH-PRB-set to its logical ECCEs according to the present invention.

FIG. 14 is a table illustrating an example of UE-specific search spaceconfiguration for ePDCCH in a wireless communication system according tothe present invention.

FIG. 15 is a diagram illustrating an example of cell aggregationprocessing according to the present invention.

FIG. 16 is a diagram illustrating an example of a TDD-FDD aggregatedwireless communications system according to the present invention.

FIG. 17 is an exemplary information element that can be used forexplicit indication of the discovery signal configuration according tothe present invention.

FIG. 18 is a flow chart diagram describing the process by which a mobilestation device educes the dormant cell on/off assumptions for a servingcell whose discovery signal has been detected according to the presentinvention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described indetail with reference to the drawings. First, physical channelsaccording to the present invention will be described.

FIG. 1 shows an illustrative communications system. Base station device1 transmits control information to mobile station device 2 throughPhysical Downlink Control Channel (PDCCH) or Enhanced PDCCH (ePDCCH) 3.This control information governs the downlink transmission of data 4 andthe uplink transmission of data 6.

The information message transmitted in the PDCCH and in the ePDCCH isscrambled with one of many RNTI (Radio Network Temporary Identifier).The used scrambling code helps to differentiate the function of themessage, for example, there is an RNTI for paging (P-RNTI), randomaccess (RA-RNTI), cell related operations such as scheduling (C-RNTI),semi-persistent scheduling (SPS-RNTI), system information (SI-RNTI),etc.

The base station device 1 and the mobile station device 2 communicatewith each other according to a series of pre-defined parameters andassumptions corresponding to a selected transmission mode (TM).Transmission modes 1 to 10 have been defined to present a plurality ofoptions covering different scenarios and use cases. For example, TM 1corresponds to single antenna transmission, TM 2 to transmit diversity,TM 3 to open-loop spatial multiplexing, TM 4 to closed-loop spatialmultiplexing, TM 5 to multi-user MIMO (Multiple Input Multiple Output),TM 6 to single layer codebook-based precoding, TM 7 to single-layertransmission using DM-RS, TM 8 to dual-layer transmission using DM-RS,TM 9 to multi-layer transmission using DM-RS, and TM 10 to eight layertransmission using DM-RS.

For a given serving cell, if the mobile station device is configured toreceive PDSCH data transmissions according to transmission modes 1-9, ifthe mobile station device is configured with a higher layer parameterepdcch-StartSymbol-r11 the starting OFDM symbol “I_(EPDCCHstart)” forEPDCCH is determined by this parameter. Otherwise, the starting OFDMsymbol for EPDCCH1 “I_(EPDCCHstart)” is given by the CFI (Control FormatIndicator) present in the PCFICH (Physical Control Format IndicatorChannel) present in the PDCCH region when there are more than tenresource blocks present in the bandwidth, and “I_(EPDCCHstart)” is givenby the CFI value +1 in the subframe of the given serving cell when thereare ten or fewer resource blocks present in the bandwidth.

For a given serving cell, if the UE is configured via higher layersignalling to receive PDSCH data transmissions according to transmissionmode 10, for each EPDCCH-PRB-set, the starting OFDM symbol formonitoring EPDCCH in subframe “k” is determined from the higher layerparameter pdsch-Start-r11 as follows:

If the value of the parameter pdsch-Start-r11 is 1, 2, 3 or 4“I_(EPDCCHstart)” is given by that parameter.

Otherwise, “I_(EPDCCHstart)” is given by the CFI value in subframe “k”of the given serving cell when there are more than ten resource blockspresent in the bandwidth, and “I_(EPDCCHstart)” is given by the CFIvalue +1 in subframe “k” of the given serving cell when there are ten orfewer resource blocks present in the bandwidth.

If subframe “k” is indicated by the higher layer parametermbsfn-SubframeConfigList-r11 or if subframe “k” is subframe 1 or 6 forTDD operation “I_(EPDCCHstart)=min(2, “I_(EPDCCHstart)”)

Otherwise “I_(EPDCCHstart)”=“I_(EPDCCHstart)”.

Different TMs are transmitted in different antenna ports. Two antennaports are said to be quasi co-located if the large-scale properties ofthe channel over which a symbol on one antenna port is conveyed can beinferred from the channel over which a symbol on the other antenna portis conveyed. The large-scale properties include one or more of delayspread, Doppler spread, Doppler shift, average gain, and average delay.A mobile station device does not assume that two antenna ports are quasico-located unless specified otherwise by the base station device.

A mobile station device configured in transmission mode 10 for a servingcell is configured with one of two quasi co-location types for theserving cell by higher layer parameter qcl-Operation to decode the PDSCHor the ePDCCH.

Type A: the mobile station device may assume the antenna ports 0-3(corresponding to CRS), 7-22 (UE-specific RS and CSI-RS), and 107-110(corresponding to DM-RS associated with ePDCCH) of a serving cell arequasi co-located with respect to delay spread, Doppler spread, Dopplershift, and average delay.

Type B: the mobile station device may assume the antenna ports 15-22(corresponding to CSI-RS resource configuration identified by the higherlayer parameter qcl-CSI-RS-ConfigNZPId-r11), the antenna ports 7-14(UE-specific RS), and the antenna ports 107-110 (corresponding to DM-RSassociated with ePDCCH) are quasi co-located with respect to delayspread, Doppler spread, Doppler shift, and average delay.

A mobile station configured in transmission mode 10 for a given servingcell can be configured with up to 4 parameter sets by the base stationdevice to decode PDSCH or ePDCCH. The mobile station device uses theparameter set according to the value of the “PDSCH RE Mapping andQuasi-Co-Location Indicator” field (PQI) for determining thePDSCH/ePDCCH RE mapping and for determining the antenna port quasico-location if the mobile station is configured with Type B quasico-location type. PQI acts as an index for the 4 configurable parametersets.

The parameter set referenced by PQI includes crs-PortsCount-r11 (numberof antenna ports), crs-FreqShift-r11 (frequency shift of the CRS),mbsfn-SubframeConfigList-r11 (definition of the subframes that arereserved for MBSFN in downlink), csi-RS-ConfigZPId-r11 (identificationof a CSI-RS resource configuration for which the mobile station deviceassumes zero transmission power), pdsch-Start-r11 (starting OFDM symbol)and qcl-CSI-RS-ConfigNZPId-r11 (CSI-RS resource that is quasi co-locatedwith the PDSCH/ePDCCH antenna ports).

In a typical network the coverage of multiple base station devicesoverlaps in some areas. A system may allow for a mobile station deviceto be served by any of these base station devices in a transparent way,without the need for the mobile station device to perform a handover toa base station device prior to receiving from it. The base stationdevice in the serving cell configures through RRC messages the quasico-location parameter set that matches the conditions of the overlappingbase station devices. The overlapping base station devices can transmitto the mobile station device with no interruption of service if themobile station device switches to the right PQI parameter set.

Base station device 10 is in a dormant state. In the dormant state, basestation device 10 does not transmit signals normally. At some giventimes base station device 10 broadcasts a signal intended to let nearbymobile station devices discover the presence of base station device 10(hereon referred to as “discovery signal” or “DS”, Discovery Signal 7 inthe figure). Mobile station device 2 is configured to listen topotential discovery signals and perform RRM (Radio Resource Management)measurements (e.g. RSRP (Reference Signal Received Power) or RSRQ(Reference Signal Received Quality)).

Reference signal received power (RSRP), is defined as the linear averageover the power contributions (in [W]) of the resource elements thatcarry discovery signal reference signals within the consideredmeasurement frequency bandwidth. For RSRP determination the discoverysignal specific RS shall be used (e.g. PSS, SSS, CRS, CSI-RS, PRS,etc.). The reference point for the RSRP shall be the antenna connectorof the UE. If receiver diversity is in use by the UE, the reported valueshall not be lower than the corresponding RSRP of any of the individualdiversity branches.

Reference Signal Received Quality (RSRQ) is defined as the ratioN*RSRP/(E-UTRA carrier RSSI), where N is the number of RB's of theE-UTRA carrier RSSI measurement bandwidth. The measurements in thenumerator and de-nominator shall be made over the same set of resourceblocks. E-UTRA Carrier Received Signal Strength Indicator (RSSI),comprises the linear average of the total received power (in [W])observed only in OFDM symbols containing reference symbols, in themeasurement bandwidth, over N number of resource blocks by the UE fromall sources, including co-channel serving and non-serving cells,adjacent channel interference, thermal noise etc. If higher-layersignalling indicates certain subframes for performing RSRQ measurements,then RSSI is measured over all OFDM symbols in the indicated subframes.The reference point for the RSRQ shall be the antenna connector of theUE. If receiver diversity is in use by the UE, the reported value shallnot be lower than the corresponding RSRQ of any of the individualdiversity branches.

Base station device 10 is expected to broadcast the discovery signal atsome predefined instants. For example, base station device 10 broadcaststhe discovery signal in one or more of a group of L subframes (“burst”,or “discovery burst”) that occur with a period of M subframes. Mobilestation device 2 is configured to monitor for discovery signals in someor all of the L subframes of some or all bursts.

Mobile station device 2 considers a dormant cell successfully detectedwhen the measured RRM of the discovery signal is equal to or exceeds aconfigured threshold or meets certain conditions. Mobile station device2 may report the results of the measurements to base station device 1,which may trigger base station device 1 to activate base station device10 (herein after also referred to as wake up or turn on)

FIG. 2 illustrates a construction example of a downlink subframe. Thedownlink transmission is performed through OFDMA. A downlink subframehas a length of 1 ms, and can be broadly thought of as divided intoPDCCH, ePDCCH and PDSCH. Each subframe is composed of two slots. Eachslot has a length of 0.5 ms. A slot is further divided into a pluralityof OFDM symbols in the time domain, each one of them being composed of aplurality of subcarriers in the frequency domain. In an LTE system oneRB includes twelve subcarriers and seven (or six) OFDM symbols. Eachsubcarrier of each OFDM symbol is a Resource Element (RE). The groupingof all the REs present in a slot composes a Resource Block (RB). Thegrouping of the two physically consecutive resource blocks present in asubframe composes a Physical Resource Block pair (PRB pair). A PRB pair(2 slots) comprises 12 subcarriers×14 OFDM symbols in the case of normalCP (cyclic prefix), and 12 subcarriers×12 OFDM symbols in the case ofextended CP. The PDCCH region occupies the REs of the first 1 to 4 OFDMsymbols of the frame.

The PDCCH region of a PRB pair spans the first 1, 2, 3 or 4 OFDMsymbols. The rest of the OFDM symbols are used as the data region(PDSCH, Physical Downlink Shared channel). The PDCCH is sent in theantenna ports 0-3, along with the CRS.

The CRS are allocated to REs across the PRB according to a pattern thatis independent of the length of the PDCCH region and the data region.The number of CRS in a PRB depends on the number of antennas that areconfigured for the transmission.

The Physical Control Format Indicator Channel (PCFICH) is allocated inthe first OFDM symbol to REs that are not allocated to CRS. The PCFICHis composed of 4 Resource Element Group (REG), each REG being composedof 4 REs. It contains a value from 1 to 3 (or 2 to 4 depending on thebandwidth), corresponding to the length of the physical downlink controlchannel (PDCCH).

The Physical Hybrid-ARQ Indicator Channel (PHICH, where ARQ stands forAutomatic Repeat-reQuest) is allocated in the first symbol to REs thatare not allocated to CRS or PCFICH. It transmits the HARQ ACK/NACKsignals for uplink transmission. The PHICH is composed of 1 REG, and isscrambled in a cell-specific manner. A plurality of PHICHs can bemultiplexed in the same REs and conform a PHICH group. A PHICH group isrepeated 3 times to obtain diversity gain in the frequency and/or timeregion.

The PDCCH is allocated in the first ‘n’ OFDM symbols (where ‘n’ isindicated by the PCFICH). The PDCCH contains the Downlink ControlInformation (DCI) messages, which may contain downlink and uplinkscheduling information, downlink ACK/NACK, power control information,etc. The DCI is carried by a plurality of Control Channel Elements(CCE). A CCE is composed of 4 consecutive REs in the same OFDM symbolthat are not occupied by CRS, the PCFICH, or the PHICH.

The CCEs are numbered starting from 0 in ascending order first offrequency and second of time. First the lowest frequency RE in the firstOFDM symbol is considered. If that RE is not occupied by other CCE, CRS,PHICH, or PCFICH, it is numbered. Otherwise the same RE corresponding tothe next OFDM symbol is evaluated. Once all OFDM symbols have beenconsidered the process is repeated for all REs in frequency order.

The REs that are not occupied by a reference signal in the data regioncan be allocated to ePDCCH or Physical Downlink Shared Channel (PDCCH).

The UE monitors a set of PDCCH candidates, where monitoring impliesattempting to decode each of the PDCCHs in the set according to allmonitored DCI formats. The set of PDCCH candidates to monitor aredefined in terms of Search Spaces (SS), where a search space “S_(k)^((L))”at a given aggregation level L is defined by a set of PDCCHcandidates.

Each UE monitors two search spaces, the UE-specific Search Space (USS)and the

Common Search Space (CSS). The USS carries information that is directedexclusively to the UE, therefore only the pertinent UE can decode it.The USS is different for each UE. USS of two or more mobile stationdevices can be partially overlapped. The CSS contains generalinformation that is directed to all UEs. All UEs monitor the same commonsearch space and are able to decode the information therein.

FIG. 3 illustrates an example downlink PRB. Some of the REs of the PRBare occupied by reference signals. The different reference signals areassociated to different antenna ports. The term “antenna port” is usedto convey the meaning of signal transmission under identical channelconditions. For example, signals sent in the antenna port 0 suffer thesame channel conditions, which may differ from those of antenna port 1.

R0-R3 correspond to Cell-specific RS (CRS), which are sent in the sameantenna ports as the PDCCH (antenna ports 0-3) and are used todemodulate the data transmitted in the PDCCH, and also to demodulate thedata transmitted in the PDSCH in some transmission modes (TM). In orderto avoid excessive interference to neighboring cells interferencecancellation procedures can be implemented.

D1-D2 correspond to DM-RS associated with ePDCCH. They are sent in theantenna ports 107-110 and serve as demodulation reference signal for themobile station device to demodulate the ePDCCH therein. The UE-specificreference signals are transmitted in the same REs when configured (notat the same time). The UE-specific reference signals are transmitted inports 7-14 and serve as demodulation reference signal for the mobilestation device to demodulate the PDSCH therein.

C1-C4 correspond to CSI-RS (Channel State Information RS). They are sentin the antenna ports 15-22 and enable the mobile station device tomeasure the channel conditions.

FIG. 4 illustrates an example downlink PRB. In this example, the REs ofthe PRB marked as R6 are occupied by positioning reference signals(PRS). The positioning reference signals are associated to antenna port6. They serve to support location services, and are usually only presentin PRBs designated specifically for PRS.

FIG. 5 illustrates a construction example of an FDD downlink subframewith a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS). The pair of PSS and SSS may be hereinafter referred to as PSS/SSS. The PSS occupies the REs in the OFDMsymbol #6 of the central 6 PRBs of the bandwidth, and the SSS occupiesthe REs in the OFDM symbol #5 of the central 6 PRBs of the bandwidth.Mobile station devices detect the PSS by blindly correlating the signalwith 3 possible PSS signals. Once a PSS is detected the mobile stationdevice gains rough synchronization with the base station device and isable to perform channel estimation to decode SSS. The mobile stationdevice can obtain the ID of the cell and more accurate synchronizationvia the SSS.

The discovery signal (DS) can be constructed as a combination of PSS,SSS, and another one or more reference signals, such as CRS, CSI-RS, orPRS. The location of the PSS and SSS signals used for this purpose canbe the same as for FDD or may be different. Alternatively, the discoverysignal can be constructed using exclusively the synchronization pairPSS/SSS. A mobile station device detecting a discovery signal in adiscovery burst proceeds to measure its RSRP or RSRQ as configured bythe base station device.

FIG. 6 illustrates a construction example of an uplink subframe. Theuplink transmission is performed through SC-FDMA (Single CarrierFrequency Division Multiple Access). The uplink resources are allocatedto physical channels such as the PUSCH (Physical Uplink Shared Channel)and the PUCCH (Physical Uplink Control Channel). In addition, uplinkreference signals are transmitted in part of the resources that wouldcorrespond to the PDSCH and the PUCCH. An uplink wireless frame iscomposed of PRB pairs. The PRB pair is the basic schedulable circuit,with a predefined frequency width (the width of a resource block) andtime length (2 slots=1 subframe).

FIG. 7 illustrates the allocation of physical uplink resources to PUCCHand PUSCH. The PUCCH PRB pairs consist of two slots with differentfrequency allocations. The PUCCH element “m” is allocated to the PUCCHPRB pair with index “m”, where “m”=0, 1, 2, 3 . . . .

The transmission of data in LTE can be done through frame structure type1 (FDD) and/or through frame structure type 2 (TDD).

For FDD, 10 subframes are available for downlink transmission and 10subframes are available for uplink transmissions in each radio frame.Uplink and downlink transmissions are separated in the frequency domain.In half-duplex FDD operation, the UE cannot transmit and receive at thesame time, while there are no such restrictions in full-duplex FDD.

A mobile station device connected to an FDD base station device receivesin a subframe “n” a PDCCH message indicating the scheduling of adownlink PDSCH. The PDCCH message contains among other information thePRBs in which the PDSCH is located and the HARQ process number assignedto it. The mobile station device attempts to decode it and, followingthe FDD HARQ timing, sends an HARQ ACK/NACK indication to the basestation device in the subframe “n+4” indicating that the reception wassuccessful (ACK) or failed (NACK). If the base station device receivesan HARQ-ACK indication, the base station device releases the HARQprocess number, which can then be used for a subsequent PDSCH.Otherwise, if the base station receives an HARQ-NACK indication (or noindication) the base station device will attempt to transmit the PDSCHto the mobile station device again in the subframe “n+8”. Theretransmitted message keeps the same HARQ process number, allowing themobile station device to combine the new retransmission with theprevious received data to increase the likelihood of a successfulreception. Therefore, for FDD, there shall be a maximum of 8 downlinkHARQ processes per serving cell.

FIG. 8 illustrates the composition of an LTE radio frame in the TimeDivision Duplex mode (TDD).

An LTE radio frame has a length of 10 ms, and is composed of 10subframes.

Each subframe can be used for downlink or uplink communication asconfigured by the eNB. The switch from downlink to uplink transmissionis performed through a special subframe that acts as switch-point.Depending on the configuration a radio frame can have 1 special subframe(switch-point periodicity of 10 ms) or 2 special subframes (switch-pointperiodicity of 5 ms).

In most cases subframes #1 and #7 are the “special subframe”, andinclude the three fields DwPTS (Downlink Pilot Time Slot), GP (GuardPeriod) and UpPTS (Uplink Pilot Time Slot). DwPTS spans a plurality ofOFDM symbols and is dedicated to downlink transmission. GP spans aplurality of OFDM symbols and is empty. GP is longer or shorterdepending on the system conditions to allow for a smooth transitionbetween downlink and uplink UpPTS spans a plurality of OFDM symbols andis dedicated to uplink transmission. DwPTS carries the PrimarySynchronization Signal (PSS). Subframes #0 and #5 carry the SecondarySynchronization Signal (SSS), and therefore cannot be configured foruplink transmission. Subframe #2 is always configured for uplinktransmission.

FIG. 9 lists the possible Uplink-Downlink configurations, where “U”denotes that the subframe is reserved for uplink transmission, “D”denotes that the subframe is reserved for downlink transmission, and “S”denotes the special subframe. The base station device transmits to themobile station device the index of the Uplink-Downlink configuration tobe used.

The base station device can transmit a second Uplink-Downlinkconfiguration index.

The subframes in which both Uplink-Downlink have the same configurationare handled as described above (they are indistinctly referred to aslegacy subframes in the rest of the documents). The subframes in whichboth Uplink-Downlink configurations differ are flexible subframes, whichare subframes that can be used for either uplink or downlink Forexample, Uplink-Downlink configuration 1 is configured as U, whileUplink-Downlink configuration 2 is configured as D or S.

Even though uplink-downlink configuration 0 through 6 as currentlydefined are shown in the figure, any embodiment of this invention isalso applicable to a potential new uplink-downlink configuration. Forexample, a new uplink-downlink configuration in which all the subframesare defined as downlink could be introduced and it would be readilyapplicable to any embodiment of the present invention. Another examplewould be a new uplink-downlink configuration in which all the subframesare defined as downlink with the exception of subframe #1, which isdefined as a special subframe. The exemplary new uplink-downlinkconfiguration could be named uplink-downlink configuration 7, or it maybe given a distinctly different name to help differentiate it from theother uplink-downlink configurations. In the rest of the document thereare instances in which a reference is made to a range of uplink-downlinkconfigurations. In those cases a potential new uplink-downlinkconfiguration as described above is not precluded from being part of therange. For example, the expression “uplink-downlink configuration 1-6”is equivalent in most cases to “uplink-downlink configuration 1-7”.

FIG. 10 illustrates the block diagram of a mobile station device thatcorresponds with the mobile station device 2. As shown in the figure,the mobile station device includes a higher layer processing circuit101, a control circuit 103, a reception circuit 105, a transmissioncircuit 107, and an antenna circuit 109. The higher layer processingcircuit 101 supports being configured with more than one cell, one ofthem as a primary cell and the rest of the cells as secondary cells, andincludes a wireless resource management circuit 1011, a schedulingcircuit 1015, and a CSI report management circuit 1017. The receptioncircuit 105 includes a decoding circuit 1051, a demodulation circuit1053, a demultiplexing circuit 1055, a radio reception circuit 1057, anda channel estimation circuit 1059. The transmission circuit 107 includesa coding circuit 1071, a modulation circuit 1073, a multiplexing circuit1075, a radio transmission circuit 1077, and an uplink reference signalcreation generation 1079.

The higher layer processing circuit 101 generates control signal tocontrol the operation of the reception circuit 105 and the transmissioncircuit 107 and outputs them to control circuit 103. In addition, theupper layer processing circuit 101 processes the operations related tothe MAC layer (Medium Access Control), the PDCP layer (Packet DataConvergence Protocol), the RLC layer (Radio Link Control), and the RRClayer (Radio Resource Control).

The wireless resource management circuit 1011 in the higher layerprocessing circuit 101 manages the configuration related to its ownoperation. In addition, the wireless resource management circuitgenerates the data that is transmitted in each channel and outputs thisinformation to the transmission circuit 107.

The scheduling circuit 1015 in the higher layer processing circuit 101reads the scheduling information contained in the DCI messages receivedvia the reception circuit 105 and outputs control information to controlcircuit 103, which in turn sends control information to receptioncircuit 105 and transmission circuit 107 to perform the requiredoperations.

In addition, the scheduling circuit 1015 decides the transmissionprocessing and the reception processing timing based on the uplinkreference configuration, the downlink reference configuration and/or thetransmission direction configuration.

The CSI report management circuit 1017 in the higher layer processingcircuit 101 identifies the CSI reference REs. The CSI report managementcircuit 1017 requests channel estimation circuit 1059 to derive thechannel's CQI (Channel Quality Information) from the CSI references REs.The CSI report management circuit 1017 outputs the CQI to thetransmission circuit 107. The CSI report management circuit 1017 setsthe configuration of the channel estimation circuit 1059.

Control circuit 103 generates control signals addressed to receptioncircuit 105 and transmission circuit 107 based on the controlinformation received from higher layer processing circuit 101. Controlcircuit 103 controls the operation of reception circuit 105 andtransmission circuit 107 through the generated control signals.

Reception circuit 105, according to the control information receivedfrom control circuit 103, receives information from the base stationdevice 1 via the antenna circuit 109 and performs demultiplexing,demodulation and decoding to it. Reception circuit 105 outputs theresult of these operations to higher layer processing circuit 101.

The radio reception circuit 1057 down-converts the downlink informationreceived from the base station device 1 via the antenna circuit 109,eliminates the unnecessary frequency components, performs amplificationto bring the signal to an adequate level, and based on the in-phase andquadrature components of the received signal transforms the receivedanalog signal into a digital signal. The radio reception circuit 1057trims the guard interval (GI) from the digital signal and performs FFT(Fast Fourier Transform) to extract the frequency domain signal.

The demultiplexing circuit 1055 demultiplexes the PHICH, the PDCCH, theePDCCH, the PDSCH, and the downlink reference signals from the extractedfrequency domain signal. In addition, the demultiplexing circuit 1055performs channel compensation to the PHICH, PDCCH, ePDCCH, and PDSCH,based on the channel estimation values received from the channelestimation circuit 1059. The demultiplexing circuit 1055 outputs thedemultiplexed downlink reference signals to the channel estimationcircuit 1059.

The demodulation circuit 1053 performs multiplication by the codecorresponding to the PHICH, performs BPSK (Binary Phase Shift Keying)demodulation to the resulting signal, and outputs the result to thedecoding circuit 1051. The decoding circuit 1051 decodes the PHICHaddressed to the mobile station device 2 and transmits the decoded HARQindicator to the higher layer processing circuit 101. The demodulationcircuit 1053 performs QPSK (Quadrature Phase Shift Keying) demodulationto the PDCCH and/or ePDCCH and outputs the result to the decodingcircuit 1051. The decoding circuit 1051 attempts to decode the PDCCHand/or the ePDCCH. If the decoding operation is successful, the decodingcircuit 1051 transmits the downlink control information and thecorresponding RNTI to the higher layer processing circuit 101.

The demodulation circuit 1053 demodulates the PDSCH addressed to mobilestation device 2 as indicated by the downlink control grant indication(QPSK, 16 QAM (Quadrature Amplitude Modulation), 64 QAM, 256 QAM, orother), and outputs the result to the decoding circuit 1051. Thedecoding circuit 1051 performs decoding as indicated by the downlinkcontrol grant indication and outputs the decoded downlink data(transport block) to the higher layer processing circuit 101.

The channel estimation circuit 1059 estimates the pathloss and thechannel conditions from the downlink reference signals received from thedemultiplexing circuit 1055 and outputs the estimated pathloss andchannel conditions to the higher layer processing circuit 101. Inaddition, the channel estimation circuit 1059 outputs the channel valuesestimated from the downlink reference signals to the demultiplexingcircuit 1055. In order to compute the CQI, the channel estimationcircuit 1059 performs measurements to the channel and/or interference.

The transmission circuit 107, according to the control informationreceived from control circuit 103, generates the uplink referencesignals, performs coding and modulation to the uplink data received fromthe higher layer processing circuit (transport block), multiplexes thePUCCH, the PUSCH and the generated uplink reference signals, andtransmits it to the base station 1 through the antenna circuit 109.

The coding circuit 1071 performs block coding, convolutional coding, orothers, to the uplink control information received from the higher layerprocessing circuit 101. In addition, the coding circuit 1071 performsturbo coding to the scheduled PUSCH data.

The modulation circuit 1073 performs modulation (BPSK, QPSK, 16 QAM, 64QAM, 256 QAM, or other) to the coded bitstream received from codingcircuit 1071 according to the downlink control indication received frombase station device 1 or to a pre-defined modulation convention for eachchannel. Modulation circuit 1073 decides the number of PUSCH streams totransmit through spatial multiplexing, maps the uplink data to thatnumber of different streams, and performs MIMO SM (Multiple InputMultiple Output Spatial Multiplexing) precoding to those streams.

Uplink reference signal generation circuit 1079 generates a bit streamfollowing a series of pre-defined rules in accordance to the PCI(Physical Cell Identity, or Cell ID) for the base station device 1 to beable to discern the signals sent from the mobile station device 2, thevalue of the bandwidth in which to place the uplink reference signals,the cyclic shift indicated in the uplink grant, and the value of theparameters related to the DMRS sequence generation. The multiplexingcircuit 1075 arranges the PUSCH modulated symbols in different streamsand performs DFT (Discrete Fourier Transform) to them according to theindications given by control circuit 103. In addition, the multiplexingcircuit 1075 multiplexes the PUCCH, the PUSCH, and the generatedreference signals in their corresponding REs in their appropriateantenna ports.

Radio transmission circuit 1077 performs IFFT (Inverse Fast FourierTransform) to the multiplexed signals, performs SC-FDMA modulation(Single Carrier Frequency Division Multiple Access) to them, adds the GIto the resulting streams, generates the digital baseband signal,transforms the digital baseband signal into an analog baseband signal,generates the in-phase and quadrature components of the analog signaland up-converts it, removes the unnecessary frequency components,performs power amplification, and outputs the resulting signal toantenna circuit 109.

FIG. 11 illustrates the block diagram of a base station device thatcorresponds with base station devices 1 and 3. As shown in the figure,the mobile station device includes a higher layer processing circuit301, a control circuit 303, a reception circuit 305, a transmissioncircuit 307, and an antenna circuit 309. The higher layer processingcircuit 301 giving support to one or more cells present in the basestation device, and includes a wireless resource management circuit3011, a scheduling circuit 3015, and a CSI report management circuit3017. The reception circuit 305 includes a decoding circuit 3051, ademodulation circuit 3053, a demultiplexing circuit 3055, a radioreception circuit 3057, and a channel estimation circuit 3059. Thetransmission circuit 307 includes a coding circuit 3071, a modulationcircuit 3073, a multiplexing circuit 3075, a radio transmission circuit3077, and a downlink reference signal creation generation 3079.

The higher layer processing circuit 301 generates control signal tocontrol the operation of the reception circuit 305 and the transmissioncircuit 307 and outputs them to control circuit 303. In addition, theupper layer processing circuit 301 processes the operations related tothe MAC layer (Medium Access Control), the PDCP layer (Packet DataConvergence Protocol), the RLC layer (Radio Link Control), and the RRClayer (Radio Resource Control).

The wireless resource management circuit 3011 in the higher layerprocessing circuit 301 generates the downlink data to transmit in thedownlink PDSCH (transport block), the system information, the RRCmessages, and the MAC CE (Control Element) and outputs it to thetransmission circuit 307. Alternatively, this information can beobtained from a higher layer. In addition, the wireless resourcemanagement circuit 3011 manages the configuration information of eachmobile station device.

The scheduling circuit 3015 in the higher layer processing circuit 301decides the frequency and subframe allocation of the physical channels(PDSCH and PUSCH), and their appropriate coding rate, modulation andtransmission power according to the channel condition report receivedfrom the mobile station 2 and the channel estimation and channel qualityparameters received from channel estimation circuit 3059. The schedulingcircuit 3015 generates control signals (for example, with the DCI format(Downlink Control Information)) to control the reception circuit 305 andthe transmission circuit 307 based on the resulting scheduling andoutputs them to the control circuit 303.

The scheduling circuit 3015 generates the report that carries thescheduling information for the physical channels (PDSCH and PUSCH) basedon the resulting scheduling.

The CSI report management circuit 3017 in the higher layer processing301 controls the CSI report of the mobile station device 2. The CSIreport management circuit 3017 transmits to the mobile station device 2the configuration information for deriving the CQI from the CSIreference signal REs via the antenna circuit 309.

Control circuit 303 generates the control signals to manage thereception circuit 305 and the transmission circuit 307 according to thecontrol signals received from the higher layer processing circuit 301.Control circuit 303 outputs these signals to the reception circuit 305and the transmission circuit 307 and controls their operation.

Reception circuit 305, according to the control information receivedfrom control circuit 303, receives information from the mobile stationdevice 2 via the antenna circuit 309 and performs demultiplexing,demodulation and decoding to it. Reception circuit 305 outputs theresult of these operations to higher layer processing circuit 3101.

The radio reception circuit 3057 down-converts the downlink informationreceived from the mobile station device 2 via the antenna circuit 309,eliminates the unnecessary frequency components, performs amplificationto bring the signal to an adequate level, and based on the in-phase andquadrature components of the received signal transforms the receivedanalog signal into a digital signal. The radio reception circuit 3057trims the guard interval (GI) from the digital signal and performs FFT(Fast Fourier Transform) to extract the frequency domain signal.

The demultiplexing circuit 3055 demultiplexes the PUCCH, the PUSCH andthe reference signals of the received signal from the radio receptioncircuit 3057. This de-multiplexing is performed according to the uplinkgrant and the wireless resource allocation information sent to themobile station 2. In addition, the demultiplexing circuit 3055 performschannel compensation of the PUCCH and the PUSCH according to the channelestimation values received from the channel estimation circuit 3059. Inaddition, the demultiplexing circuit 3055 gives the demultiplexed uplinkreference signal to the channel estimation circuit 3059.

The demodulation circuit 3053 performs IDFT (Inverse Discrete FourierTransform) to the PUSCH, obtains the modulated symbols, and performsdemodulation (BPSK, QPSK, 16 QAM, 64 QAM, or other) for each PUCCH andPUSCH symbol according to the modulation configuration transmitted tothe mobile station 2 in the uplink grant notification or according toanother pre-defined configuration. The demodulation circuit 3053separates the symbols received in the PUSCH according to the MIMO SMprecoding configuration transmitted to the mobile station 2 in theuplink grant notification or according to another pre-definedconfiguration.

The decoding circuit 3051 decodes the received uplink data in the PUSCCHand the PUSCH according to the coding rate configuration transmitted tothe mobile station 2 in the uplink grant notification or according toanother pre-defined configuration, and outputs the resulting stream tothe higher layer processing circuit 301. In the case of re-transmittedPUSCH the decoding circuit 3051 decodes the received demodulated bitsusing the coded bits that are held in the HARQ buffer in the higherprocessing circuit 301. The channel estimation circuit 3059 estimatesthe channel conditions and the channel quality using the uplinkreference signal received from the demultiplexing circuit 3055, andoutputs this information to the demultiplexing circuit 3055 and thehigher layer process circuit 301.

The transmission circuit 307, according to the control informationreceived from control circuit 303, generates the downlink referencesignals, prepares the discovery signal if indicated by control 303,prepares the downlink control information including the HARQ indicatorreceived from the higher layer processing circuit 301, performs codingand modulation of the downlink data, multiplexes the result with thePHICH, the PDCCH, the ePDCCH, the PDSCH and the downlink referencesignal, and transmit the resulting signal to the mobile station device 2via the antenna circuit 309.

The coding circuit 3071 performs block coding, convolutional coding,turbo coding, or other, to the HARQ indicator received from the higherlayer processing 301, the downlink control information and the downlinkdata, according to the coding configuration decided by the wirelessresource management circuit 3011 or according to another pre-definedconfiguration.

The modulation circuit 3073 performs modulation (BPSK, QPSK, 16 QAM, 64QAM, 256 QAM, or other) to the coded bitstream received from codingcircuit 3071 according to the modulation configuration decided by thewireless resource management circuit 3011 or according to anotherpre-defined configuration.

The downlink reference signal generation circuit 3079 generates downlinkreference signals well known by the mobile station device 2 according tosome pre-defined rules and employing the PCI (Physical Cell Identity)value, which allows the mobile station device 2 to discern thetransmission of the base station device 1. The multiplexing circuit 3075multiplexes the modulated symbols in each channel and the generateddownlink reference signals in their corresponding REs in theirappropriate antenna port.

The radio transmission circuit 3077 performs IFFT (Inverse Fast FourierTransform) to the multiplexed symbols, OFDM modulation, adds the guardinterval to the OFDM symbols, generates the digital baseband signal,transforms the digital baseband signal into an analog baseband signal,generates the in-phase and quadrature components of the analog signaland up-converts it, removes the unnecessary frequency components,performs power amplification, and outputs the resulting signal toantenna circuit 309.

The number of available resources for transmission of control orinformation data depends on the reference signals present in eachresource block. The base station device is configured to avoid thetransmission of data in these REs by a proper resource element mapping.

The mobile station device assumes the resource element mapping that isused at any given time to retrieve the data. The data is mapped insequence to REs on the associated antenna port which fulfill that theyare part of the EREGs assigned for the EPDCCH transmission, they areassumed by the UE not to be used for CRS or for CSI-RS, and they arelocated in an OFDM symbol that is equal or higher than the starting OFDMsymbol indicated by “I_(EPDCCHstart)”.

In the PDCCH region a CCE is defined to always have 4 available REs totransmit information. In order to do this the CCE configuration presentssome variations depending on the number of CRS present or the reach ofthe PHICH. The result is that the PDCCH messages always have the samenumber of bits.

However, in the ePDCCH/PDCCH region the number of bits is variable. Inorder to be able to use all the available REs the base station mobilemust accommodate the data to them. This is achieved by rate matching.

The rate matching operation generates a stream of bits of the requiredsize by varying the code rate of the turbo code operation. The ratematching algorithm is capable of producing any arbitrary rate. Thebitstreams from the turbo encoder undergo an interleave operationfollowed by bit collection to create a circular buffer. Bits areselected and pruned from the buffer to create a single bitstream withthe desired code rate.

FIG. 12 contains the values that a mobile station device monitors foreach aggregation level in the USS and the CSS. The aggregation level isthe number of CCEs that a PDCCH uses. The mobile station device monitorsa number of PDCCH candidates M(L) for each aggregation level. For thecommon search space L can take one of two values, L=4 or L=8. The numberof candidates the UE monitors is M(L)=4 for L=4 and MN=2 for L=8. Thesize of the search space of each of the cases is 16 CCEs.

The basic circuit of the Enhanced PDCCH (ePDCCH) is the EnhancedResource Element Group (EREG). The REs of a PRB pair are cyclicallynumbered from 0 to 15 in ascending order of frequency and OFDM symbolskipping the REs that may contain DMRS (DeModulation Reference Signals).The same transmission processing that is applied to the PDSCH is appliedto the DMRS, which allows the UE to obtain the information it needs tobe able to demodulate the data. EREG, is composed of all the REs withnumber ‘i’, where i=0, 1, . . . 15.

However, the number of REs that can be used is not fixed. The REs usedfor PDCCH, CRS and CSI-RS (Channel State Information Reference Signal)cannot be used for ePDCCH. The CSI-RS are transmitted periodically toenable the UE to measure the channel conditions of up to 8 antennas, andit is not defined for special subframe configurations.

The control information is transmitted in Enhanced CCEs (ECCEs), whichare composed of 4 or 8 EREGs, depending on the number of REs that areavailable for transmission in each ECCE for a given configuration.

There can be 1 or 2 sets of ePDCCH-sets simultaneously, each oneindependently configurable and spanning 1, 2, 4 or 8 PRB pairs. TheePDCCH is sent in the antenna ports 107-110, along with the DM-RS.

FIG. 13 illustrates the mapping of the ECCEs of the ePDCCH in thePRB-pairs of ePDCCH-set “i” (where “i” is either 0 or 1, and “1” is alsoeither 0 or 1 while fulfilling “1” is not equal to “i”). Each PRB-pairis composed of 16 EREGs. The EREGs of all the PRB-pairs together can beconsidered as the EREGs of the ePDCCH-set. A PRB pair comprises 16EREGs, which can compose 4 or 2 ECCEs. In the example of the figure oneECCE is assumed to be composed of 4 EREGs.

In a localized allocation, each ECCE of the ePDCCH is composed of EREGsbelonging to a single a PRB pair. Due to all the REGs being in arelatively narrow band, higher benefits can be obtained throughprecoding and scheduling.

In a distributed allocation, each ECCE of the ePDCCH is composed ofEREGs belonging to different PRB pairs. Due to the frequency hoppingperformed to the REGs, the robustness is increased through frequencydiversity.

In consideration to localized or distributed allocation of the controlinformation, ePDCCH set 0 does not condition ePDCCH set 1 (if present).ePDCCH set 0 and ePDCCH set 1 are defined for any combination oflocalized and/or distributed transmission mapping.

UE-specific search space is defined for ePDCCH as ePDCCH USS (alsoreferred to as eUSS). The search space of each ePDCCH-PRB-set isindependently configured.

FIG. 14 contains the number of ECCEs that constitute an ePDCCH for eachePDCCH format. Case A applies for normal subframes and normal downlinkCP when DCI formats 2/2A/2B/2C/2D are monitored and the number ofavailable downlink resource blocks of the serving cell is 25 or more; orfor special subframes with special subframe configuration 3, 4, 8 andnormal downlink CP when DCI formats 2/2A/2B/2C/2D are monitored and thenumber of available downlink resource blocks of the serving cell is 25or more; or for normal subframes and normal downlink CP when DCI formats1A/1B/1D/1/2/2A/2B/2C/2D/0/4 are monitored, and when “n_(EPDCCH)38 <104;or for special subframes with special subframe configuration 3, 4, 8 andnormal downlink CP when DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 aremonitored, and when “n_(EPDCCH)”<104. Otherwise, case B is used.

The quantity “n_(EPDCCH)” (the number of REG available in an ECCE) for aparticular mobile station device and referenced above is defined as thenumber of downlink REs in a PRB-pair configured for possible EPDCCHtransmission of a EPDCCH-set fulfilling that they are part of any one ofthe 16 EREGs in the PRB-pair, they are assumed by the UE not to be usedfor CRS or for CSI-RS, and they are located in an OFDM symbol “1” equalor higher than the starting OFDM symbol (“1” is equal to or more than“I_(EPDHHHStart)”).

The format of the DCI depends on the purpose the ePDCCH is transmittedfor. Format 0 is usually transmitted for uplink scheduling and uplinkpower control. Format 1 is usually transmitted for downlink SIMO (SingleInput Multiple Output) scheduling and uplink power control. Format 2 isusually transmitted for downlink MIMO scheduling and uplink powercontrol. Format 3 is usually transmitted for uplink power control.Format 4 is usually transmitted for uplink scheduling of up to fourlayers.

FIG. 15 is a diagram illustrating an example of cell aggregation(carrier aggregation) processing according to the present invention. Inthe figure, the horizontal axis represents the frequency domain and thevertical axis represents the time domain. In the illustrated cellaggregation processing illustrated, three serving cells (serving cell 1,serving cell 2, and serving cell 3) are aggregated. One of the pluralityof aggregated serving cells is a primary cell (PCell). The primary cellis a serving cell having functions equivalent to those of a cell in LTE.

The serving cells other than the primary cell are secondary cells(SCells). The secondary cells have functions which are more limited thanthe primary cell, and are mainly used to transmit and receive the PDSCHand/or PUSCH. For example, the mobile station device 2 performs randomaccess using only the primary cell. Also, the mobile station device 2may not necessarily receive paging and system information transmitted onthe PBCH and PDSCH of the secondary cells.

The carriers corresponding to serving cells in the downlink are downlinkcomponent carriers (DL CCs), and the carriers corresponding to servingcells in the uplink are uplink component carriers (UL CCs). The carriercorresponding to the primary cell in the downlink is a downlink primarycomponent carrier (DL PCC), and the carrier corresponding to the primarycell in the uplink is an uplink primary component carrier (UL PCC). Thecarriers corresponding to the secondary cells in the downlink aredownlink secondary component carriers (DL SCCs), and the carrierscorresponding to the secondary cells in the uplink are uplink secondarycomponent carriers (UL SCCs).

The base station device 1 necessarily sets both the DL PCC and the ULPCC as a primary cell. Also, the base station device 1 is capable ofsetting only the DL SCC or both the DL SCC and the UL SCC as a secondarycell. Further, the frequency or carrier frequency of a serving cell iscalled a serving frequency or serving carrier frequency, the frequencyor carrier frequency of a primary cell is called a primary frequency orprimary carrier frequency, and the frequency or carrier frequency of asecondary cell is called a secondary frequency or secondary carrierfrequency.

The mobile station device 2 and the base station device 1 first startcommunication using one serving cell. Through this communication, thebase station device 1 sets a set of one primary cell and one or aplurality of secondary cells for the mobile station device 2 by using anRRC signal (radio resource control signal). The base station device 1 iscapable of setting a cell index for a secondary cell. The cell index ofthe primary cell is constantly zero. The cell index of the same cell maybe different among the mobile station devices 1. The base station device1 is capable of instructing the mobile station device 2 to change theprimary cell using handover.

The serving cell 1 is the primary cell, and the serving cell 2 and theserving cell 3 are the secondary cells. Both the DL PCC and UL PCC areset in the serving cell 1 (primary cell), both the DL SCC-1 and UL SCC-1are set in the serving cell 2 (secondary cell), and only the DL SCC-2 isset in the serving cell 3 (secondary cell).

The channels used in the DL CCs and UL CCs have the same channelstructure as that in LTE. Each of the DL CCs has a region to which thePHICH, the PCFICH, and the PDCCH are mapped, which is represented by aregion hatched with oblique lines, and a region to which the PDSCH ismapped, which is represented by a region hatched with dots. The PHICH,the PCFICH, and the PDCCH are frequency-multiplexed and/ortime-multiplexed. The region where the PHICH, the PCFICH, and the PDCCHare frequency-multiplexed and/or time-multiplexed and the region towhich the PDSCH is mapped are time-multiplexed. In each of the UL CCs,the region to which the PUCCH represented by a gray region is mapped,and the region to which the PUSCH represented by a region hatched withhorizontal lines is mapped are frequency-multiplexed.

In cell aggregation, up to one PDSCH can be transmitted in each of theserving cells (DL CC), and up to one PUSCH can be transmitted in each ofthe serving cells (UL CC). In the example of the figure, up to threePDSCHs can be simultaneously transmitted using three DL CCs, and up totwo PUSCHs can be simultaneously transmitted using two UL CCs.

Furthermore, in cell aggregation, a downlink assignment includinginformation indicating the allocation of radio resources for the PDSCHin the primary cell, and an uplink grant including informationindicating the allocation of radio resources for the PUSCH in theprimary cell, are transmitted on the PDCCHs of the primary cell. Theserving cell in whose PDCCH are transmitted a downlink assignmentincluding information indicating the allocation of radio resources forthe PDSCH in the secondary cell and an uplink grant includinginformation indicating the allocation of radio resources for the PUSCHin the secondary cell is set by the base station device 1. This settingmay vary among mobile station devices.

If a setting is made so that a downlink assignment including informationindicating the allocation of radio resources for the PDSCH and an uplinkgrant including information indicating the allocation of radio resourcesfor the PUSCH in a certain secondary cell are to be transmitted using adifferent serving cell (hereafter cross-carrier scheduling, as opposedto self-scheduling), the mobile station device 2 does not decode thePDCCH in this secondary cell. For example, if a setting is made so thata downlink assignment including information indicating the allocation ofradio resources for the PDSCH and an uplink grant including informationindicating the allocation of radio resources for the PUSCH in theserving cell 2 are to be transmitted using the serving cell 1(cross-carrier scheduling), and that a downlink assignment includinginformation indicating the allocation of radio resources for the PDSCHand an uplink grant including information indicating the allocation ofradio resources for the PUSCH in the serving cell 3 are to betransmitted using the serving cell 3 (self-scheduling), the mobilestation device 2 decodes the PDCCH in the serving cell 1 and the servingcell 3, and does not decode the PDCCH in the serving cell 2.

The base station device 1 sets, for each serving cell, whether or not adownlink assignment and an uplink grant include a carrier indicator,which indicates the serving cell whose PDSCH or PUSCH radio resourcesare allocated by the downlink assignment and the uplink grant. The PHICHis transmitted in the serving cell in which the uplink grant includingthe information indicating the allocation of radio resources for thePUSCH for which the PHICH indicates an ACK/NACK has been transmitted.

The base station device 1 is capable of deactivating and activating asecondary cell which has been set for the mobile station device 2 usingMAC (Medium Access Control) CE (Control Element). The mobile stationdevice 2 does not receive any physical downlink channels and signals anddoes not transmit any physical uplink channels and signals in adeactivated cell, and does not monitor downlink control information forthe deactivated cell. The mobile station device 2 regards a secondarycell which is newly added by the base station device 1 as a deactivatedcell. Note that the primary cell is not deactivated.

In an FDD (Frequency Division Duplex) wireless communication system, aDL CC and a UL CC corresponding to a single serving cell are constructedat different frequencies. In a TDD (Time Division Duplex) wirelesscommunication system, a DL CC and a UL CC corresponding to a singleserving cell are constructed at the same frequency, and an uplinksubframe and a downlink subframe are time-multiplexed at a servingfrequency.

FIG. 16 is a diagram illustrating an example of the configuration ofradio frames in a TDD-FDD CA (Carrier Aggregation) wirelesscommunication system. This case is indistinctly referred to as TDD-FDDCA, or simply TDD-FDD in the document. The horizontal axis representsthe frequency domain and the vertical axis represents the time domain.White rectangles represent downlink subframes, rectangles hatched withoblique lines represent downlink subframes, and rectangles hatched withdots represent special subframes. The number (#i) assigned to eachsubframe is the number of the subframe in the radio frame.

In the figure, an FDD serving cell and a TDD serving cell areaggregated. The FDD serving cell has a band configured for downlink inwhich all the subframes are used for downlink transmission, and anotherband configured for uplink in which all the subframes are used foruplink transmission. The TDD serving cell has only one band, where thedownlink subframes, uplink subframes, and special subframes aremultiplexed in time. In the example of the figure the TDD serving celluses the UL/DL configuration 2.

If the FDD serving cell is the PCell and the TDD serving cell is theSCell the PCell follows its own HARQ timing, while the SCell follows thetiming of the PCell. Instead of following the downlink set associationdescribed above, a mobile station device connected to a TDD SCell sendsthe HARQ indication of a message to the PCell through the FDD PUCCHfollowing the FDD HARQ timing. As this channel is always available themobile station device sends the HARQ indication in the subframe “n+4”,where “n” represents the subframe in which the reception of the relatedPDSCH took place, and a retransmission would occur in the subframe“n+8”.

The maximum number of simultaneous HARQ processes that can occur in acase in which a TDD serving cell is aggregated with an FDD serving celldepends on the configuration of the primary cell and the secondary cell.

Particularly, the case in which the TDD serving cell is the primary cellpresents some challenges, because an FDD secondary cell adapts its HARQtiming to that of the TDD primary cell, therefore needing to addressmore HARQ processes than it is currently possible for FDD serving cells.

FIG. 17 shows an example of an information element (IE) that can be usedfor explicit indication of the discovery signal configuration. Inparticular, the information element is labeled asDiscoverySignalMonitoring-Config-r12. Higher layer parameters such asIEs are provided by higher layer signaling (or RRC signaling).

DiscoverySignalMonitoring-Config-r12 contains a parametermonitoringWindow, with information about the location of the discoverysignal bursts; rrmMeasurement, configuring the mobile station devicewith the type of RRM measurement the mobile station device is expectedto perform; and discoverySignalList, with information about theconfiguration of the discovery signals.

The parameter monitoringWindow comprises periodicity, which isconfigured as DSPeriod, and is the value in subframes of the periodicityof the discovery signal burst; burstSize, which is the number ofsubframes that a burst may span, up to a maximum of maxBurst; andoffset, which is a parameter giving an indication of when the next burstwill take place. In one example the discovery signal could take placewith a periodicity of 100 subframes, spanning 3 subframes, the nextdiscovery signal burst taking place 32 subframes after the RRCconfiguration message.

The parameter rtinMeasurement indicates the mobile station whether theRRM measurement to be applied to the discovery signal should be RSRP orRSRQ.

The parameter discoverySignalList gives the configuration of one or morepossible types of discovery signals, and presents them in groups of twoor more candidates. If no group is configured, then the mobile stationdevice is not expected to monitor for discovery signals.

The IE DiscoverySignalCandidateGroup comprises at least two differentcandidates of discovery signals, configured by the IE Discovery SignalCandidate.

The IE DiscoverySignalCandidate comprises the configuration of apossible discovery signal candidate. There are a potentially largeamount of discovery signals to be used. In an embodiment of theinvention discovery signal there are defined candidates based on thereference signal of the discovery signal (DiscoverySignal-RSType), onthe subframe location of the discovery signal in the burst(DiscoverySignal-SubframeLocation), on the resource element in use(DiscoverySignal-ResourceElement), on the measured and perceived powerof the discovery signal (DiscoverySignal-IncreasingPower), and on theperiodicity of the discovery signal with regard to the periodicity ofthe discovery signal burst periods (DiscoverySignal-Periodicity).

DiscoverySignal-RSType comprises a parameter indicating the presence ofa PSS signal, a indicating the presence of a SSS signal, and a parameterindicating the presence of other reference signal. In an embodiment ofthe invention the possible additional reference signals are none (onlyPSS/SSS or a subset thereof), CRS, CSI-RS, or PRS. In another embodimentof the invention PSS/SSS are considered intrinsic to the discoverysignal and no parameter is defined to indicate their presence. Inanother embodiment of the invention more than one additional referencesignal type can be configured in the same signal via a bitmap or two ormore of the appropriate parameters.

DiscoverySignal-SubframeLocation comprises a parameter offset, which inone embodiment of the invention points to a subframe of the discoverysignal burst where the discovery signal candidate can be transmitted. Inanother embodiment of the invention there are more than one of thesevalues, the discovery signal candidate being able to be transmitted inany or all of the pointed subframes.

DiscoverySignal-ResourceElement comprises a parameter resourceElementthat configures one among a plurality of options of resource elements tobe used by the discovery signal. In one embodiment of the invention thediscovery signal uses PSS/SSS and CSI-RS. The parameter resourceElementindicates which of the resource elements CSI-RS can be in is actuallyused in the discovery signal (for example, a subsection of the resourceelements, or all, or none, etc.).

DiscoverySignal-IncreasingPower comprises a parameter giving a powerthreshold over which a signal can be considered as a positive match forthe configured candidate.

DiscoverySignal-Periodicity comprises a parameter giving a threshold ofperiodicity in discovery signal burst periods for the discovery signal.If the period of the discovery signal of a dormant cell is equal to orbelow the configured parameter the discovery signal can be considered asa positive match for the configured candidate.

The IE MeasObjectEUTRA defines the measurement conditions under whichRRM measurements are performed (e.g. frequency, bandwidth, etc.). Ablack list is defined with the cell IDs of serving cells that the mobilestation device should not perform RRM measurements on if detected. Anoptional cell list is also defined to accommodate the need for ameasurement offset for certain cells. The list contains the cell IDs andthe offset to be applied to measurements on those cells.

The IE ReportConfigEUTRA specifies criteria for triggering of an E-UTRAmeasurement reporting event. The E-UTRA measurement reporting events arelabelled AN with N equal to 1, 2 and so on.

Event A1: Serving becomes better than absolute threshold;

Event A2: Serving becomes worse than absolute threshold;

Event A3: Neighbour becomes amount of offset better than PCell;

Event A4: Neighbour becomes better than absolute threshold;

Event A5: PCell becomes worse than absolute threshold1 AND Neighbourbecomes better than another absolute threshold2;

Event A6: Neighbour becomes amount of offset better than SCell.

The threshold or thresholds associated with each of the events in the IEReportConare configured separately through RRC configuration. The celldetection described in all embodiments can be based on the measurementreporting. For example, a UE can assume that a cell is detected when oneof the E-UTRA measurement reporting events is triggered for its signal.

The methods and criteria specified in the IE MeasObjectEUTRA andReportConfigEUTRA are applicable to discovery signals. In one embodimentof the invention a sole threshold is defined for all the discoverysignal candidates. In another embodiment of the invention each discoverysignal candidate is configured with a different threshold, which doesnot preclude some of these thresholds from being configured with thesame value. As an example, the IE MeasObjectEUTRA is modified tocomprise the discovery signal measurement conditions under which RRMmeasurements are performed. A black list is defined with the cell IDs ofserving cells for which the mobile station device should not perform RRMmeasurements if their discovery signal is detected. An optional celllist is also defined to accommodate the need for a measurement offsetfor certain cells. The list contains the cell IDs and the offset to beapplied to measurements of the discovery signals of those cells.

FIG. 18 illustrates a flow chart for the decision about the dormant cellon/off configuration assumptions inferred by the mobile station devicethrough discovery signal detection.

The figure illustrates only two conditions, but in some cases there arethree, four, or more different outcomes depending on a set ofconditions. This figure is also used for those cases, understanding thatan extension of it to accommodate the multiplicity of possibleconditions is a trivial exercise. Alternatively, those cases can bethought as a series of binary conditions, in which condition 1corresponds to a single condition and condition 2 corresponds to abundle of all the remaining conditions together. If condition 2 ischosen, the process is repeated using one of the bundled conditions asthe new condition 1, and the remaining ones as the new bundled condition2. This process is iterated until a single condition is reached.

The mobile station device monitors for discovery signals with an RSRP orRSRQ level over a configured threshold, which are then considered to bedetected, and checks the condition described herein. The dormant cellon/off configuration assumptions 1, 2, . . . shown in the flow chart canbe different each time the condition is checked. Alternatively, themobile station device may be configured with a different threshold foreach different discovery signal candidate, in which case the decisionabout whether a discovery signal is considered detected or not relies onthe configured threshold for the matching discovery signal candidate.

In one embodiment of the invention a mobile station device is configuredwith two candidate discovery signals belonging to the same discoverysignal candidate group. The mobile station device assumes that thedormant cell is in the transition time between off and on states, orshortly going to wake up and enter the on state, if a discovery signalmatching the first configured discovery signal candidate is received,and that the dormant cell is going to remain dormant for an indefiniteamount of time if a discovery signal matching the second configureddiscovery signal candidate is received. Alternatively, the mobilestation device may be configured with three or more discovery signalcandidate signals, each giving an idea of the remaining off timedepending on their configuration.

In one embodiment of the invention the base station device transmitsdiscovery signals only in the off state. In another embodiment of theinvention the base station device transmits discovery signals regardlessof its state. In another embodiment of the invention the base stationdevice transmits a first configured discovery signal candidate when itis in “off” state and not going to wake up soon; the base station devicetransmits a second configured discovery signal candidate during thetransition time; and the base station device transmits a thirdconfigured discovery signal candidate while in the on state. In anotherembodiment of the invention the base station device transmits the secondconfigured discovery signal candidate during the transition time andduring the on state time. In another embodiment of the invention thebase station device transmits the first and second configured discoverysignal candidates during the transition time and only the secondconfigured discovery signal candidate during the on state. Mobilestation devices are expected to be configured to support one or more ofthese behaviors.

In an embodiment of the invention the exact remaining time in subframesfrom the detection of a discovery signal matching a particular discoverysignal candidate until the base station device completes its transitionto the on state is known and equal to “remaining time”. A base stationdevice knows the transition time required to completely switch from theoff state to the on state (“transition time”), and the base stationdevice also knows the timing of the discovery signal bursts; the basestation device starts the transition process “transition time -remaining time” subframes prior to the transmission of a discoverysignal of the pertinent discovery signal candidate type.

In an embodiment of the invention, the mobile station device may sendinformation to the primary cell regarding the detected dormant cellswhose discovery signals have good measured RRM and match a secondconfigured discovery signal candidate, a third configured discoverysignal candidate, or beyond; if instead the mobile station devicedetects a discovery signal matching a first configured discovery signalcandidate the mobile station device may start monitoring PDCCH/EPDCCHcorresponding to that serving cell. The mobile station device may do soif the detected discovery signal matching the first configured discoverysignal candidate has the highest RRM measurement value among thedetected discovery signals. In another embodiment of the invention anoffset is configured or predetermined to give priority to the discoverysignals matching the first configured discovery signal candidates, evenwhen their measured RRM is not the highest among all detected discoverysignals. Alternatively, an offset could be configured or predeterminedto give priority to discovery signals matching a second configureddiscovery signal candidate or beyond.

In an embodiment of the invention a first configured discovery signalcandidate is configured with a certain combination of reference signals,while a second configured discovery signal candidate is configured witha different combination of reference signals, and subsequent discoverysignal candidates are configured with different combinations ofreference signals. The mobile station device searches for all possiblediscovery signal candidates and makes assumptions about a dormant cellon/off configuration according to the discovery signal candidate adetected RS matches with.

In another embodiment of the invention a first configured discoverysignal candidate is expected by the mobile station device in a subset ofone or more of the discovery signal burst subframes; a second configureddiscovery signal candidate are expected in a different subset ofsubframes; a third configured discovery signal candidate and beyond areexpected in different subframes. The mobile station device monitors forall possible discovery signal candidates and makes assumptions about thedormant cell on/off configuration according to the discovery signalcandidate the detected RS corresponds to.

In another embodiment of the invention the differentiation betweendiscovery signal candidates depends on their RE mapping. A firstconfigured discovery signal candidate is expected by the mobile stationdevice to have discovery signal RS in a subset of the possible resourceelements the RS can be transmitted in. A second configured discoverysignal candidate and beyond are expected to have RS in different subsetsof the possible resource elements the RS can be transmitted in. Theremay be resource elements in common between each of the possible pair ofsubsets of resource elements configured for the different discoverysignal candidates. In another embodiment of the invention, a resourceelement can only belong to a subset corresponding to one discoverysignal candidate. The mobile station device monitors for all possiblediscovery signal candidates and makes assumptions about the dormant cellon/off configuration according to the discovery signal candidate thedetected RS corresponds to.

In another embodiment of the invention dormant cells increase thetransmission power of their discovery signal progressively as the timeto become active approaches. The mobile station device considers adetected discovery signal to match a first configured discovery signalcandidate if the measured RRM is over a certain threshold. Multiplediscovery signal candidates can be configured in this manner, the mobilestation device considering the detected discovery signals to match oneof the configured discovery signals candidates and assuming differenton/off configurations depending on the case.

In another embodiment of the invention only one candidate is configured,the mobile station device assuming a given configuration for a cellwhose discovery signal matches the configured discovery signalcandidate.

In another embodiment of the invention a set of dormant cells transmittheir discovery signals with a period that is a multiple of the periodof the discovery signal burst. The dormant cells increase theperiodicity as the time to become active approaches. A mobile stationdevice configured with multiple discovery signal candidates assumes aconfiguration set for the cell whose discovery signal matches one of theconfigured discovery signal candidates.

In another embodiment of the invention only one candidate is configured,the mobile station device assuming a given configuration for a cellwhose discovery signal matches the configured discovery signalcandidate.

In another embodiment of the invention there are configured differentgroups of candidates with different configurations. The mobile stationdevice monitors all of them and makes assumptions based on the discoverysignal candidate the detected discovery signal matches.

The above described discovery signal candidate configurations and acombination thereof may be comprised without limitations in a samediscovery signal candidate group. For example, a first configureddiscovery signal candidate may use CRS and be transmitted in a firstsubset of subframes inside the burst, while a second configureddiscovery signal candidate may use CSI-RS and be transmitted in a secondsubset of subframes inside the burst. Additionally, a third configureddiscovery signal may use PRS and be transmitted in any of the subframesof the discovery signal burst (that is, different configured discoverysignals candidates may be transmitted in the same subframe(s) as others,the main differentiator between those other discovery signal candidatesbeing their subframe location). In another example, a first configureddiscovery signal candidate is configured with CSI-RS and a subset of thepossible CSI-RS resource elements, a second configured discovery signalcandidate is configured with CSI-RS and a different subset of possibleresource elements, and a third configured discovery signal candidate maybe configured with PRS.

In another embodiment of the invention the parameter monitoring Windowis a parameter inside the IE DiscoverySignalCandidateGroup. Differentcandidate groups are transmitted following different periodicity,discovery signal burst size, and/or offset.

Alternatively, any of the above described sets of discovery signalcandidates could be fixed and predefined, without the requirement of thebase station device having to configure their values to the mobilestation devices.

In an embodiment of the invention the mobile station device startsmonitoring the PDCCH/EPDCCH of a dormant active cell under certaindormant cell on/off assumptions. For example, the UE starts monitoringPDCCH/EPDCCH of a dormant cell that is becoming active in a short periodof time.

Alternatively, the mobile station device waits a given amount of timeafter detecting a first configured discovery signal candidate and startsmonitoring PDCCH/EPDCCH for that cell.

If a mobile station device is configured withDiscoverySignalMonitoring-Config-r12, and if the discovery signalindicated by DiscoverySignalCandidate 1 is detected, then the mobilestation device shall not monitor PDCCH/EPDCCH.

If a mobile station device is configured withDiscoverySignalMonitoring-Config-r12, and if the discovery signalindicated by DiscoverySignalCandidate 0 is detected, then the mobilestation device shall monitor PDCCH/EPDCCH.

In another embodiment of the invention the mobile station device startsa legacy procedure for cell detection and handover if a first configureddiscovery signal candidate is detected.

If a mobile station device is configured withDiscoverySignalMonitoring-Config-r12, and if the discovery signalindicated by DiscoverySignalCandidate 0 is detected, then the UE shallperform legacy procedure (e.g. PSS/SSS/CRS detection).

In another embodiment of the invention the RRM report of the mobilestation device is different depending on the detected dormant cellson/off assumptions.

If a mobile station device is configured withDiscoverySignalMonitoring-Config-r12, and if the discovery signalindicated by DiscoverySignalCandidate 1 is detected, then the mobilestation device shall report the RRM measurement result of the smallcell.

If a mobile station device is configured withDiscoverySignalMonitoring-Config-r12, and if the discovery signalindicated by DiscoverySignalCandidate 0 is detected, then the mobilestation device shall measure RRM (RSRP/RSRQ) using legacy procedure(e.g. by CRS).

A program operated in the base station device and the mobile stationdevices according to the present invention may be a program (programcausing a computer to function) for controlling a CPU (CentralProcessing Unit) or the like so as to realize the functions of theabove-described embodiments according to the present invention. Theinformation handled in these devices is temporarily stored in a RAM(Random Access Memory) during the processing of the information, beingthereafter stored in various kinds of ROMs such as a flash ROM (ReadOnly Memory) or an HDD (Hard Disk Drive), and is read out, corrected, orwritten by the CPU as necessary.

Part of the mobile station devices and the base station device accordingto the above-described embodiments may be implemented by a computer. Inthat case, a program for implementing this control function may berecorded on a computer-readable recording medium, and a computer systemmay be caused to read and execute the program recorded on the recordingmedium.

Here, the “computer system” is a computer system included in each of themobile station devices or the base station device, and includes hardwaresuch as an OS and peripheral devices. The “computer-readable recordingmedium” is a portable medium such as a flexible disk, a magneto-opticaldisk, a ROM, or a CD-ROM, or a storage device such as a hard diskincluded in the computer system.

Furthermore, the “computer-readable recording medium” may also includean object that dynamically holds a program for a short time, such as acommunication line used to transmit the program via a network such asthe Internet or a communication line such as a telephone line, and anobject that holds a program for a certain period of time, such as avolatile memory in a computer system serving as a server or a client inthis case. Also, the above-described program may implement some of theabove-described functions, or may be implemented by combining theabove-described functions with a program which has already been recordedon a computer system.

Furthermore, part or whole of the mobile station devices and the basestation device in the above-described embodiment may be implemented asan LSI, which is typically an integrated circuit, or as a chip set. Theindividual functional blocks of the mobile station devices and the basestation device may be individually formed into chips, or some or all ofthe functional blocks may be integrated into a chip. The method forforming an integrated circuit is not limited to LSI, and may beimplemented by a dedicated circuit or a general-purpose processor. In acase where the progress of semi-conductor technologies produces anintegration technology which replaces an LSI, an integrated circuitaccording to the technology may be used.

While some embodiments of the present invention have been described indetail with reference to the drawings, specific configurations are notlimited to those described above, and various design modifications andso forth can be made without deviating from the gist of the presentinvention.

REFERENCE SIGNS LIST

1 Base station device

2 Mobile station device

3 PDCCH/ePDCCH

4 Downlink data transmission

5 Physical Uplink Control Channel

6 Downlink data transmission

7 Discovery signal

10 Dormant base station device

101 Higher layer processing circuit

1011 Wireless resource management circuit

1015 Scheduling circuit

1017 CSI report management circuit

103 Control circuit

105 Reception circuit

1051 Decoding circuit

1053 Demodulation circuit

1055 Demultiplexing circuit

1057 Radio reception circuit

1059 Channel estimation circuit

107 Transmission circuit

1071 Coding circuit

1073 Modulation circuit

1075 Multiplexing circuit

1077 Radio transmission circuit

1079 Uplink reference signal generation circuit

109 Antenna circuit

301 Higher layer processing circuit

3011 Wireless resource management circuit

3015 Scheduling circuit

3017 CSI report management circuit

303 Control circuit

305 Reception circuit

3051 Decoding circuit

3053 Demodulation circuit

3055 Demultiplexing circuit

3057 Radio reception circuit

3059 Channel estimation circuit

307 Transmission circuit

3071 Coding circuit

3073 Modulation circuit

3075 Multiplexing circuit

3077 Radio transmission circuit

3079 Uplink reference signal generation circuit

309 Antenna circuit

1. A mobile station device comprising a first circuit configured with aplurality of discovery signal candidates; and a second circuit adaptedto perform monitoring for the discovery signal candidates; and a thirdcircuit adapted to identify a detected discovery signal with one of thediscovery signal candidates.
 2. The mobile station device according toclaim 1, wherein the discovery signal candidates differ between them inthe combination of reference signals they are configured with, a firstdiscovery signal candidate being based on a combination of referencesignals; and a second discovery signal candidate being based on adifferent combination of reference signals; and subsequently configureddiscovery signal candidates being based on a combination of referencesignals that is different from the combination of reference signals ofthe previously configured discovery signal candidates.
 3. The mobilestation device according to claim 1, wherein the discovery signalcandidates differ between them in the subset of subframes within thediscovery signal burst they are transmitted on, a first discovery signalcandidate being transmitted on a subset of subframes; and a seconddiscovery signal candidate being transmitted on a different subset ofsubframes; and subsequently configured discovery signal candidates beingtransmitted on a subset of subframes that is different from the subsetof subframes of the previously configured discovery signal candidates.4. The mobile station device according to claim 1, wherein the discoverysignal candidates differ between them in the subset of resource elementswithin the physical resource block they are transmitted on, a firstdiscovery signal candidate being transmitted on a subset of resourceelements; and a second discovery signal candidate being transmitted on adifferent subset of resource elements; and subsequently configureddiscovery signal candidates being transmitted on a subset of resourceelements that is different from the subset of resource elements of thepreviously configured discovery signal candidates.
 5. The mobile stationdevice according to claim 1, wherein the discovery signal candidatesdiffer between them in the transmission power used for theirtransmission, a first discovery signal candidate being transmitted witha given transmission power; and a second discovery signal candidatebeing transmitted with a different transmission power; and subsequentlyconfigured discovery signal candidates being transmitted with atransmission power that is different from the transmission power of thepreviously configured discovery signal candidates.
 6. The mobile stationdevice according to claim 1, wherein the discovery signal candidatesdiffer between them in the period they are transmitted with, the periodbeing a multiple of the period of the discovery signal burst, a firstdiscovery signal candidate being transmitted with a given period; and asecond discovery signal candidate being transmitted with a differentperiod; and subsequently configured discovery signal candidates beingtransmitted with a period that is different from the period of thepreviously configured discovery signal candidates.
 7. The mobile stationdevice according to claim 1, wherein the mobile station device assumes astate or set of parameters of the serving cell transmitting a detecteddiscovery signal based on the discovery signal candidate the detecteddiscovery signal matches with.
 8. The mobile station device of claim 7further comprising a circuit to compare the RRM measurement of thedetected discovery signals' cells; and another circuit to report to theprimary serving cell the identities of the cells with the largest RRMmeasured values.
 9. The mobile station device of claim 7 furthercomprising a circuit to compare the RRM measurement of the detecteddiscovery signals' cells; and another circuit to monitor thePDCCH/EPDCCH of a cell whose detected discovery signal's RRM measurementis over a configured threshold and matches one of the configureddiscovery signal candidates.
 10. The mobile station device of claim 9,wherein the RRM measurements is performed with an offset whose valuedepends on the configured discovery signal candidate the discoverysignal matches with before performing RRM measurement comparisons. 11.The mobile station device of claim 7, wherein the mobile station devicestarts a procedure for cell detection in a cell whose discovery signalmatches one of the configured discovery signal candidates.
 12. Themobile station device of claim 11 further comprising a circuit toprepare a first RRM report format for RRM measurements of discoverysignals matching a first subset of discovery signal candidates; andanother circuit to prepare a second RRM report format for RRMmeasurements of discovery signals matching the discovery signalcandidates that are not part of the first subset.
 13. The mobile stationdevice of claim 12 further comprising a circuit to compare the RRMmeasurement values of the detected discovery signals, wherein the mobilestation device prepares only the first or the second RRM report formatbased on the discovery signal candidate the detected discovery signalwith the largest RRM measurement value matches with.
 14. (canceled) 15.A base station device comprising a first circuit configured with aplurality of discovery signal candidates; and a second circuit adaptedto select a discovery signal candidate according to a set of configuredconditions; and a third circuit adapted to prepare and transmit theselected discovery signal candidate.
 16. The base station deviceaccording to claim 15, wherein the discovery signal candidates differbetween them in the combination of reference signals they are configuredwith, a first discovery signal candidate being based on a combination ofreference signals; and a second discovery signal candidate being basedon a different combination of reference signals; and subsequentlyconfigured discovery signal candidates being based on a combination ofreference signals that is different from the combination of referencesignals of the previously configured discovery signal candidates. 17.The base station device according to claim 15, wherein the discoverysignal candidates differ between them in the subset of subframes withinthe discovery signal burst they are transmitted on, a first discoverysignal candidate being transmitted on a subset of subframes; and asecond discovery signal candidate being transmitted on a differentsubset of subframes; and subsequently configured discovery signalcandidates being transmitted on a subset of subframes that is differentfrom the subset of subframes of the previously configured discoverysignal candidates.
 18. The base station device according to claim 15,wherein the discovery signal candidates differ between them in thesubset of resource elements within the physical resource block they aretransmitted on, a first discovery signal candidate being transmitted ona subset of resource elements; and a second discovery signal candidatebeing transmitted on a different subset of resource elements; andsubsequently configured discovery signal candidates being transmitted ona subset of resource elements that is different from the subset ofresource elements of the previously configured discovery signalcandidates.
 19. The base station device according to claim 15, whereinthe discovery signal candidates differ between them in the transmissionpower used for their transmission, a first discovery signal candidatebeing transmitted with a given transmission power; and a seconddiscovery signal candidate being transmitted with a differenttransmission power; and subsequently configured discovery signalcandidates being transmitted with a transmission power that is differentfrom the transmission power of the previously configured discoverysignal candidates.
 20. The base station device according to claim 15,wherein the discovery signal candidates differ between them in theperiod they are transmitted with, the period being a multiple of theperiod of the discovery signal burst, a first discovery signal candidatebeing transmitted with a given period; and a second discovery signalcandidate being transmitted with a different period; and subsequentlyconfigured discovery signal candidates being transmitted with a periodthat is different from the period of the previously configured discoverysignal candidates.
 21. (canceled)